Misc. Coding

Mainly for me to remember this but if you're using the excellent Versioning bundle for RavenDB then you'll find you quickly need to work out a way to get the latest version of a document if querying on any field other than ID (I *believe* ID actually only gets the latest one). The little index definitions below do just that (the secome one is just adding another field to the map so I can query by that...useful example)...